Washington — “Birthright citizenship” – the policy of granting US citizenship to every child born on US soil – may be one of the hottest political issues of the summer. In recent weeks, some congressional Republicans have become increasingly vocal about their desire to deny such recognition to the children of illegal immigrants, saying it is a lure that draws foreigners to sneak into the country.

However, as a practical matter, changing this policy would be extremely difficult. That’s because it is in the Constitution – or, rather, it is based on the 14th Amendment to the Constitution. The amendment begins this way: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

Passage of a new constitutional amendment would require a two-thirds “aye” vote in the House and Senate, plus the approval of the legislatures of three-quarters of the 50 states. In today’s polarized political environment, it is hard to envision that happening.

Some proponents of changing the citizenship rules argue that their purpose can be accomplished with legislation. That might be a little easier to get through Congress – but it would almost certainly be vetoed by President Obama while he remains in office. Even if a future GOP chief executive signed such a bill, it would face inevitable close federal court review.

“Politically it can’t be done, and it is simply a distraction from seeking true immigration reform,” argued Bill Ong Hing, a professor at the University of San Francisco School of Law and supporter of birthright citizenship, in a recent conference call with reporters.

The issue itself is not a newcomer to Washington. Bills to deny citizenship to the children of parents in the US illegally have been introduced in Congress with regularity in recent years.

But this year, a number of top GOP lawmakers have said they would support at least exploring limits on the 14th Amendment. Sen. Lindsey Graham (R) of South Carolina said recently on Fox News that he was thinking of introducing a proposed constitutional amendment because birthright citizenship is a magnet drawing illegals into the US.

Birthright citizenship “attracts people here for all the wrong reasons,” Senator Graham said.

“In certain parts of our country, clearly, our schools, our hospitals are being overrun by illegal immigrants, a lot of whom came here just so their children could become US citizens,” said Representative Boehner on NBC’s “ Meet the Press” on Sunday.

Proponents of changing US citizenship policies say that “birth tourism,” in which travel firms in China, Turkey, and elsewhere sell travel packages designed to allow pregnant women to give birth in the US, is a troubling new element. Legislation, they say, is all that’s needed to change the situation.

The drafters of the 14th Amendment never intended that it should apply to the children of foreigners present in the US, they say. It was meant to extend citizenship to African-Americans. Legislation could clarify this situation, say some conservatives.

But supporters of birthright citizenship say that that reading of the history of the 14th Amendment is untrue and that to alter the policy would be to alter the nation’s democratic character.